Straight hole drilling device



Jafl- 2 1934. v E. sTRoUD A STRAIGHT HOLE DRILLING DEVICE Filed April29, 1931 Patented Jan. 2, 1934 STATES STRAIGHT HOLE Voet E. Stroud,

Application April .29, 1931.

3 Claims.

My invention relates to well drilling tools and relates especially to adrilling device which will tend toward maintaining a straight hole.

In drilling wells by the rotary method the drill bit is often caused towork to the side so as to produce a hole which is not straight. Thislateral olsetting of the drill is generally caused by inclinedsubterranean structure.

It is the principal object of my invention to 19 provide a device whichmay be operated in a a drilling tool adapted to be secured to the lowerend of a string of drill pipe, this drilling tool having cutter meanssecured to the lower end thereof and slidably supporting a pilot memberwhich may be projected from the outer body of the drilling tool intopiloting engagement with the bottom of the hole being bored.

It is a further object of the invention to provide a drilling tool ofthe above character having an outer body adapted to support outercutters and an inner body adapted to support inner cutters, there beinga keyed engagement between said outer and inner bodies for permittingthe inner body to slide downwardly into a position of projection fromthe lower end of the outer body, but at all times causing the inner bodyto be positively rotated by the outer body.

A further object of the invention is to provide a drilling tool of theabove character adapted to use replaceable cutters.

Further objects and advantages of the invention will be made evidentthroughout the following part of the specification.

' Referring to the drawing, which is for illustrative purposes only,

Fig. l is a vertically sectioned view showing a preferred embodiment ofmy invention and illustrating one manner in which it may be employed inthe drilling of a well.

Fig. 2 is an enlarged fragmentary sectional 50 view showing the lowerend of the outer tubular member and further showing the inner member inraised position relative to the outer tubular member.

Fig. 3 is an enlarged cross section on a plane 55 represented by theline 3 3 of Fig. 1.

DRILLING DEVICE Belllower, Calif.

Serial No. 533,678

(Cl. .Z-61) 4 is an enlarged fragmentary section on a plane representedby the line 4-4 oi Fig. 2.

The preferred form of my invention shown in Fig. l includes an outertubular body 11 having a threaded pin 12 at its upper end adapted toreceive a collar 13 which is in turn screwed onto the lower end 14 or" astring of drill pipe. The tubular body 11 has a main bore 15 extendingfrom an upper end point 16 to a lower end point 17, and beinglongitudinally splined so as to provide longitudinal grooves 18. Thelower ends of the grooves 18 are closed by a threaded ring or sleeve 20which screws into a threaded counterbore 21, this ring or sleeve 20being of such length that it has a lower end portion 22 projecving belowthe lower end 23 of the tubular body 1l. An inner tubular member 24 isslidable within the bore 15 of the body 11, this inner tubular memberhaving ribs 25 formed thereon to it the longitudinal grooves 18 oi" thebody l1. The ribs 25 are substantiaily in the center of the member 24 sothat the ribs 25 act as a division between the upper end 26 and thelower end 27 of the inner tubular member 24. The upper end 25 projectsthrough packing means 3G situated in a counterbore 31 which leadsupwardly from the upper extremity 16 of the main bore 15 and includes alower ring 32 which closes the upper ends or the longitudinal grooves18, a body of packing material 33, an upper ring 34, and a ring nut 35which screws into the internal threads 36 formed in the upper portion ofthe counterbore 31. The extreme lower end 37 of the member 24 isrounded, as shown in Figs. 1 and 2, and has a transverse slot 38, asshown in Fig. 4, adapted to receive an inner cutter member 40 which isheld in place in the slot by means 0f a locking screw 4l which isreceived in a threaded opening 42 in the end 37 and passes through ahole 43 in the inner cutter 40. A mud circulation passage 44 extendsaxially through the member 24 from the upper end thereof to a point 45adjacent the extreme lower end 37, and from the lower end or the passage44 diagonal passages 46 extend downwardly and outwardly so as todischarge streams of drilling mud in iront oi the blades 47 and 43comprising the inner cutter 40. i

Lugs 5o project outwardly from the lower end or the tubular body 11 andreceive bolts 51 for bolting to the lugs the upper blade extensions 52of outer cutter blades 53 forming an outer cutter 54. The blades 53 aretied together by a ring 55 which is preferably formed or cast integrallywith the blades and. is adapted to fit against the lower end face of thebody 11, as shown in Fig. 2. The ring 55 ts around the lower portion 27of the inner member 24 and has a counterbore 56 in the upper portionthereof to t the downwardly extending end 22 of the threaded ring 20 sothat the engagement of the counterbore 56 with the projecting end 22will centralise the cutter 54. As shown in Fig. 2, the inner cutter 40is of such width that the blades 47 and 48 thereof overlap the inneredges 60 of the blades 53 of the outer cutter 54, and when the innermember 24 is raised to its highest position relative to the outer member11, as shown in Fig. 2, the cutters 40 and 54 assume the relativepositions shown, and the lower cutting edges 6l and 62 of the inner andouter cutter members lie in a flat plane perpendicular to the axis ofthe members 11 and 24.

A preferred manner of using the device is as follows: In Fig. 1 thedrilling device is shown in the lower portion or" a well bore 65, thelower end 66 of which is slightly offset rightwardly. Under ordinaryconditions this rightward offset at the lower end of the hole wouldcontinue, thereby producing a hole of such croolredness that placing ofthe casing would be difficult. With my device, however, it is possibleto lift the outer tubular member ll by raising upwardly on the string ofdrill pipe 14, whereupon the inner member 24 will project downwardlyfrom the outer member l1. By raising the outer member 11 through adistance greater than the length of the lower portion 27 of the member24, it is possible to lift the inner cutter 40 from the bottom 67, asindicated by dotted lines 68, permitting the cutter then to becentralized on the axis A-A of the portion of the hole 65 above theoffset lower end 66. Then, by lowering the drill pipe 14 and the partsattached thereto, the cutter 40 may be caused to advance verticallydownwardly from the position in which it is shown by dotted lines 68into engagement with the ilat bottom 67 of the hole 65 and to thenpenetrate the bottom in the manner shown so as to form a pilot orcounterbore 69, which counterbore 69 will of course be eccentric withrespect to the lower offset end 66 but will be axially aligned with thestraight upper portion of the hole 65. The continued downward movementof the drill pipe 14 will cause the outer body ll and the outer cutter54 to advance downwardly, and during such downward advance the innermember 24 will guide the outer body axially so that the outer cutter 54will cut along the dotted lines 7l, concentric with the axis A-A. Whenthe outer cutter 54 reaches and overlaps the inner cutter 40, they willprogress downwardly together in overlapped position such as shown inFig. 2. In the use of my new drilling device the drilling operation isconducted by steps. For instance, fifteen feet of hole will be drilledwith the inner and outer cutters 40 and 54 in overlapped relationship asshown in Fig. 2, and the drill pipe will then be raised so as to allowthe inner portion 24 to be extended from the outer body 11 due tohydraulic pressure of drilling mud against the upper end of the innermember 24, and a pilot bore 69 will then be iormed in the mannerpreviously described. After the forming of such pilot bore, anotherfteen feet or other selected length of hole will be bored, and thedevice again raised and a pilot bore formed. Therefore, the hole will becontinued by repeating this process of boring a short length of hole andthen forming a pilot bore.

Although I have herein shown and described my invention in simple andpractical form, it is recognized that certain parts or elements thereofare representative of other parts, elements, or mechanisms which may beused in substantially the same manner to accomplish substantially thesame results; therefore, it is to be understood that the invention isnot to be limited to the details disclosed herein but is to be accordedthe full scope of the following claims.

I claim as my invention:

1. A drilling device of the character described, including: an outertubular member having its upper end adapted to be secured to the lowerend of a string of drill pipe, and having a bore with longitudinalgrooves in the wall of such bore; an inner member slidable within saidbore, said inner member having radially projecting ribs adapted toengage said longitudinal grooves, the lower end oi said inner memberbeing adapted to receive an inner cutter of a character to make pilotengagement with the bottom or" the hole being drilled; a ring itted intothe lower end of said cuter tubular member, ring providing a lower endwall for said grooves in said outer tubular member; and means on thelower end of said outer tubular member adapted to receive an outercutter member.

2. A drilling device of the character described, including: an outertubular member having its upper en d adapted to be secured to the lowerend of a string of drill pipe, and having a bore with longitudinalgrooves in the wall oi such bore; an inner member slidable within saidbore, said inner member having radially projecting ribs adapted toengage said longitudinal grooves, the lower end o said inner memberbeing adapted to receive an inner cutter of a character to make pilotengagement with the bottom of the hole being drilled; a ring fitted intothe lower end of said outer tubular member, said ring providing a lowerend wall for said grooves in said outer tubular member; means on thelower end of said outer tubular member adapted to receive an outercutter member; and an outer cutter member secured to said means on thelower end of said outer tubular member, said outer cutter member havingan opening therethrough for the passage of the lower end of said innermember.

3. A drilling device of the character described, including: an outertubular member having its upper end adapted to be secured to the lowerend oi a string of drill pipe, and having a bore with longitudinalgrooves in the wall of such bore; an inner member slidable within saidbore, said inner member having radially projecting ribs adapted toengage said longitudinal grooves, the lower end of said inner memberbeing adapted to re eive an. inner cutter of a character to make pilotengagement with the bottom of the hole being drilled; a ring fitted intothe lower end of said outer tubular member, said ring providing a lowerend wall for said grooves in said outer tubular' member; means on thelower end of said outer tubular member adapted to receive an outercutter member; and an outer cutter member secured to said means on thelower end of said outer tubular member, said outer cutter member havingan opening therethrough for the passage of the lower end of said innermember, the lower cutting edges of said outer cutter member and saidinner cutter lying substantially in a radial plane when said innercutter is held in fully raised position by said inner member.

VOET E. STROUD.

